The present invention relates to a vertically arranged centrifugal pump with a support bearing which is provided above the pump and absorbs the axial and radial forces exerted by the centrifugal pump and which is lubricated and, optionally, cooled by a medium conducted via the support bearing, the centrifugal pump being driven via a shaft which is extended through a housing surrounding the support bearing and into a housing or housing part belonging to the conveying region of the centrifugal pump, and a shaft seal being provided which separates the region containing the conveying medium from the surrounding environment.
Pumps of this type comprise one or more stages which are usually arranged in a cylindrical housing. Such pumps are used, for example, as condensate pumps. The support bearing of such a pump is exposed primarily to an axial load, but the bearing also has to absorb radial forces. It has hitherto been customary to arrange the support bearing above the flow-carrying housing of the centrifugal pump, in a bearing housing separated from the flow-carrying housing. The support bearing either has been lubricated by grease or oil stored in the bearing housing, or the support bearing has been lubricated and, under certain circumstances, also cooled, by a separately provided medium, for example oil. This medium, which is conveyed under pressure, has thus been supplied to, and discharged from, the support bearing via respective lubricant pipelines. Since the drive shaft of the centrifugal pump has been extended through the bearing housing of the support bearing into the flow-carrying housing, i.e., the housing belonging to the conveying region of the centrifugal pump, it has been necessary to use three different shaft seals.
Above all, the expense involved in the version outlined in terms of the provision and the supply and discharge of a separate lubricant and coolant for the support bearing, but also the outlay in terms of the various shaft seals, have prompted the desire to provide a version which decisively reduces this outlay. The object on which the invention is based is founded on this desire.